Soluble glycoprotein v for treating thrombotic diseases

ABSTRACT

A soluble polypeptide comprising a modified glycoprotein V (GPV) lacking a functional transmembrane domain for use in the treatment or prevention of a thrombotic disease in a subject, said treatment or prevention comprising administering to the subject an effective amount of said soluble polypeptide.

BACKGROUND

Platelet activation and subsequent thrombus formation at sites of vascular injury is crucial for normal hemostasis, but it can also cause myocardial infarction and stroke (Coughlin S R. Nature. 2000; 407: 258-64). Platelet adhesion and activation is a multistep process involving multiple platelet receptor-ligand interactions. Upon vessel wall injury, circulating platelets are rapidly decelerated by transient interactions of the glycoprotein (GP) Ib-V-IX complex with von Willebrand factor (vWF) immobilized on the exposed subendothelial extracellular matrix (e.g. on collagen) (Shapiro M J, et al. The Journal of Biological Chemistry. 2000; 275: 25216-21). This interaction retains platelets close to the vessel wall and facilitates the contact between GPVI and collagen (Nieswandt B, et al. Blood. 2003; 102: 449-61). GPVI-collagen interactions induce an intracellular signaling cascade leading to platelet activation and the release of secondary platelet agonists, such as thromboxane A₂ (TxA₂) and adenosine diphosphate (ADP). These soluble agonists together with locally produced thrombin further contribute to platelet activation through G protein (G_(i), G_(q), G_(12/13)) coupled receptors (Offermanns S. Circulation research. 2006; 99: 1293-304). All these signaling pathways synergize to induce complex cellular responses, such as activation of integrins, release of granule contents and the provision of a pro-coagulant surface for the activation of the coagulation cascade (Nakanishi-Matsui M, et al. Nature. 2000; 404: 609-13; Cunningham M A, et al. The Journal of experimental medicine. 2000; 191: 455-62). The final thrombus is embedded in a fibrin network to withstand the shear forces generated by the flowing blood. The stabilization of a newly formed thrombus is essential to arrest bleeding at sites of vascular injury. However, if this process occurs in an uncontrolled manner it may also lead to thrombotic events causing life-threatening disease states such as myocardial infarction or ischemic stroke. Consequently, antiplatelet and anticoagulant drugs, used alone or in combination, are of major importance in treating cardio- and cerebrovascular diseases (May F, et al. Blood. 2009; 114: 3464-72; Schroder J, et al. Mol Cell Biol. 2009; 29: 1083-94; Braun A, et al. Blood. 2009; 113: 2056-63). Whilst current anti-platelet therapies reduce the recurrence of vascular events, the increased risk of bleeding due to platelet inhibition is a particular concern for patients who have experienced stroke, and a further subset of patients remain refractory to anti-platelet approaches (Pleines I, et al. Pflugers Archiv: European journal of physiology. 2009; 457: 1173-85), underscoring the need for novel anti-platelet strategies.

Their central role in platelet adhesion puts two receptor complexes in the focus of platelet research: i) the GPIb-V-IX complex which interacts with vWF immobilized on the injured vessel wall or on activated platelets and thereby recruits platelets from blood stream to the reactive surface under conditions of elevated shear. ii) GPIIb/IIIa (integrin αIIbβ3), a receptor for fibrinogen and vWF that requires inside-out activation mediated by agonist receptors, contributes to firm shear-resistant platelet adhesion and is essential for aggregate formation. The GPIb-V-IX complex is composed of 4 related transmembrane GPs: GPIbα, GPIbβ, GPV and GPIX, which are associated in a stoichiometry of 2:4:2:1 (Luo S-Z et al. Blood. 2007; 109(2): 603-9). Within this complex, GPIbα and GPIbβ are disulfide-linked and noncovalently associated with GPIX. GPV is noncovalently associated with GPIb-IX (Nieswandt B, et al. Journal of Thrombosis and Haemostasis. 2009; 7: 206-9). Approximately 30,000 copies of the GPIb-IX complex are found on the surface of human platelets (Varga-Szabo D, et al. Journal of Thrombosis and Haemostasis. 2009; 7: 1057-66). Loss of GPIb-V-IX function causes Bernard-Soulier syndrome (BSS), a severe bleeding disorder. BSS is characterized by abnormal, giant circulating platelets with defective adhesion to vWF and reduced thrombin responsiveness (Canobbio I, et al. Cellular signalling. 2004; 16: 1329-44). While lack or dysfunction of GPIb or GPIX are associated with BSS, no loss of function mutation in GP5 has been reported and the lack of GPV in mice does not lead to a BSS-phenotype (Ramakrishnan V, et al. PNAS. 1999; 96: 13336-41; Kahn M L, et al. Blood. 1999; 94: 4112-21). GPV is the only subunit which is not required for the correct expression of the complex (Dong J, et al. Journal of Biological Chemistry. 1998; 273: 31449-54). WO 95/02054 A2, U.S. Pat. No. 6,005,089 and Lanza F, et al. Journal of Biological Chemistry. 1993; 268: 20801-20807 disclose the sequence and structure of the human GPV gene and the amino acid sequence of human GPV. GPV is highly glycosylated and contains a thrombin cleavage site leading to quantitative removal of GPV from the platelet surface and the generation of soluble GPV (sGPV) in the presence of thrombin (Ravanat C, et al. Blood. 1997; 89: 3253-62; Azorsa D O, et al. Thrombosis and Haemostasis. 1999; 81: 131-8; White G C, et al. Thrombosis Research. 38: 641-648). The soluble human GPV generated by thrombin cleavage has the amino acid sequence as shown in SEQ ID NO:10. Of note, this thrombin cleavage site is conserved in the mouse, rat and human protein (Ravanat C, et al. Blood. 1997; 89: 3253-62). However, in contrast to protease-activated receptor (PAR) 4-deficient mice, which do not respond upon thrombin stimulation (Kahn M L, et al. Blood. 1999; 94: 4112-21; Kahn M L, et al. Nature. 1998; 394: 690-4), Gp5^(−/−) mice display grossly normal platelet functionality. Besides thrombin, GPV can, like GPIbα or GPVI, be cleaved by sheddases of the ‘a disintegrin and metalloproteinase’ (ADAM) family, most notably ADAM17 (also referred to as the tumor necrosis factor-converting enzyme, TACE) and ADAM10 (Garton K J, et al. Journal of Biological Chemistry. 2001; 276: 37993-8001; Gardiner E E, et al. Blood. 2004; 104: 3611-7; Bergmeier W, et al. Thrombosis and Haemostasis. 2004; 91: 951-8), which results in a slightly longer variant of sGPV. However, thrombin is considered as the major regulator of GPV surface expression. SGPV levels differ enormously between plasma and serum (17.3±6.3 ng/ml vs. 1.2±0.17 μg/ml, respectively) (Azorsa D O, et al. Thrombosis and Haemostasis. 1999; 81: 131-8) and sGPV levels are slightly elevated under certain pathological conditions, such as ischemic stroke (39.4 ng/ml compared to 28.1 ng/ml in controls) (Wolff V, et al. Stroke. 2005; 36: e17-9). To date, no role for sGPV in thrombosis or hemostasis has been described.

SUMMARY OF THE INVENTION

The inventors surprisingly found that soluble GPV has an antithrombotic effect, without affecting the bleeding time. Thus, the present invention provides an antithrombotic agent comprising soluble GPV. The present invention relates to the following embodiments (1) to (36):

-   (1) A soluble polypeptide comprising a modified glycoprotein V (GPV)     for use in the treatment and/or prevention of a thrombotic disease     in a subject, said treatment and/or prevention comprising     administering to the subject an effective amount of said soluble     polypeptide. -   (2) The soluble polypeptide for use according to item (1), wherein     the thrombotic disease is selected from the group consisting of     thrombo-inflammatory conditions, venous thrombosis, arterial     thrombosis, capillary thrombosis, portal vein thrombosis, renal vein     thrombosis, jugular vein thrombosis, cerebral venous sinus     thrombosis, thrombus formation during or after contacting blood with     an artificial surface, in particular extracorporeal membrane     oxygenation (ECMO), atherosclerosis, arthritis, coagulopathy, deep     venous thrombosis (DVT), disseminated intravascular coagulopathy     (DIC), a chronic or acute thromboembolism, pulmonary     thromboembolism, Budd-Chiari syndrome, Paget-Schroetter diseases,     stroke and myocardial infraction. -   (3) The soluble polypeptide for use according to any one of the     preceding items, wherein said modified GPV is a truncated GPV. -   (4) The soluble polypeptide for use according to any one of the     preceding items, wherein said modified GPV or truncated GPV consists     of a fragment of the extracellular domain of a native GPV, said     fragment having a length of at least 6 amino acids. -   (5) The soluble polypeptide for use according to any one of the     preceding items, wherein said modified GPV or truncated GPV consists     of a fragment of the extracellular domain of a native GPV, said     fragment having a length of at least 8 amino acids. -   (6) The soluble polypeptide for use according to any one of the     preceding items, wherein said modified GPV or truncated GPV consists     of a fragment of the extracellular domain of a native GPV, said     fragment having a length of at least 30 amino acids. -   (7) The soluble polypeptide for use according to any one of the     preceding items, wherein said modified GPV or truncated GPV consists     of a fragment of the extracellular domain of a native GPV, said     fragment having a length of at least 100 amino acids. -   (8) The soluble polypeptide for use according to any one of the     preceding items, wherein said modified GPV or truncated GPV consists     of a fragment of the extracellular domain of a native GPV, said     fragment having a length of at least 250 amino acids. -   (9) The soluble polypeptide for use according to any one of the     preceding items, wherein said modified GPV or truncated GPV consists     of a fragment of the extracellular domain of a native GPV, said     fragment having a length of at least 400 amino acids. -   (10) The soluble polypeptide for use according to any one of     items (4) to (9), wherein said fragment has anti-thrombotic     activity. -   (11) The soluble polypeptide for use according to any one of     items (4) to (10), wherein said fragment does not substantially     affect bleeding time upon administration. -   (12) The soluble polypeptide for use according to any one of     items (4) to (11), wherein said native GPV consists of the amino     acid sequence as shown in SEQ ID NO:3, and the extracellular domain     substantially consists of amino acids 1-503 of SEQ ID NO:3. -   (13) The soluble polypeptide for use according to any one of     items (4) to (11), wherein said native GPV consists of the amino     acid sequence as shown in SEQ ID NO:7, and the extracellular domain     substantially consists of amino acids 1-502 of SEQ ID NO:7. -   (14) The soluble polypeptide for use according to any one of the     preceding items, wherein said soluble polypeptide is a non-naturally     occurring polypeptide. -   (15) The soluble polypeptide for use according to item (14), further     comprising a half-life-extending moiety. -   (16) The soluble polypeptide for use according to item (15), wherein     said half-life-extending moiety is conjugated to said modified GPV,     either directly or via a linker. -   (17) The soluble polypeptide for use according to item (16), wherein     said half-life-extending moiety is selected from the group     consisting of hydroxyethyl starch (HES), polyethylene glycol (PEG),     polysialic acids (PSAs) and albumin binding ligands, e.g. fatty acid     chains. -   (18) The soluble polypeptide for use according to item (15), wherein     said half-life-extending moiety is a heterologous amino acid     sequence fused to said modified GPV, either directly or via a     linker. -   (19) The soluble polypeptide for use according to item (18), wherein     the half-life extending heterologous amino acid sequence comprises     or consists of a polypeptide selected from the group consisting of     albumin and a fragment thereof having a length of at least 100 amino     acids, immunoglobulin constant regions and fragments thereof, e.g.     the Fc fragment, transferrin and fragments thereof, the C-terminal     peptide of human chorionic gonadotropin, solvated random chains with     large hydrodynamic volume (XTEN), homo-amino acid repeats (HAP),     proline-alanine-serine repeats (PAS), afamin, alpha-fetoprotein,     Vitamin D binding protein, polypeptides capable of binding under     physiological conditions to albumin or immunoglobulin constant     regions, and combinations thereof. -   (20) The soluble polypeptide for use according to any one of the     preceding items, wherein said soluble polypeptide is obtainable by     recombinant expression in eukaryotic cells. -   (21) The soluble polypeptide for use according to item (20), wherein     said eukaryotic cells are mammalian cells. -   (22) The soluble polypeptide for use according to item (21), wherein     said mammalian cells are CHO cells. -   (23) The soluble polypeptide for use according to item (20), wherein     said eukaryotic cells are insect cells, e.g. Sf9 cells. -   (24) The soluble polypeptide for use according to any one of     items (1) to (19), wherein said soluble polypeptide is obtainable by     recombinant expression in prokaryotic cells, e.g. in bacterial     cells. -   (25) The soluble polypeptide for use according to any one of the     preceding items, wherein said soluble polypeptide has     anti-thrombotic activity. -   (26) The soluble polypeptide for use according to any one of the     preceding items, wherein said soluble polypeptide does not     substantially affect bleeding time upon administration. -   (27) The soluble polypeptide for use according to any one of the     preceding items, wherein said treatment and/or prevention further     comprises administering to said subject an antiplatelet or an     anticoagulant drug. -   (28) A pharmaceutical composition comprising a soluble polypeptide     as defined in any one of items (1) to (26), and a pharmaceutically     acceptable excipient. -   (29) The pharmaceutical composition of item (28), wherein the     soluble polypeptide does not consist of the amino acid sequence as     shown in SEQ ID NO:10. -   (30) A method of treating a thrombotic disease in a subject,     comprising administering to the subject an effective amount of a     soluble polypeptide as defined in any one of items (1) to (26), or     the pharmaceutical composition of item (28) or (29). -   (31) A method of preparing the soluble polypeptide according to any     one of items (1) to (26), comprising expressing a nucleic acid     encoding the soluble polypeptide as defined in any one of items (1)     to (26) in a mammalian cell, and recovering the soluble polypeptide     from the culture medium. -   (32) A non-naturally occurring soluble GPV as defined in any one of     items (5) to (26). -   (33) The non-naturally occurring soluble GPV of item (32), which     does not consist of the amino acid sequence as shown in SEQ ID     NO:10. -   (34) A soluble GPV which does not consist of the amino acid sequence     as shown in SEQ ID NO:10. -   (35) A pharmaceutical kit comprising (i) a soluble polypeptide     according to any one of items (1) to (26), and (ii) an antiplatelet     or an anticoagulant drug other than said soluble polypeptide. -   (36) The pharmaceutical kit of item (35), wherein the soluble     polypeptide does not consist of the amino acid sequence as shown in     SEQ ID NO:10.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1: Soluble GPV has an antithrombotic effect in an aortic injury model. The abdominal aorta was mechanically injured by a single firm compression with a forceps and blood flow was monitored with a Doppler flowmeter. Time to final occlusion is shown. A,B) Occlusion times after injection of soluble human GPV (A: shGPV; B: shGPV-Albumin-Fusion-Protein (AFP)) or soluble murine GPV (C: smGPV). Each symbol represents one individual mouse. In cases where mice were unable to form occlusive thrombi Fisher's exact test was used to calculate P-values. * P<0.05; ** P<0.01; *** P<0.001

FIG. 2: Soluble human GPV protects from ischemic stroke. Mice were subjected to 60 min of transient middle cerebral artery occlusion (tMCAO). Brain infarct volumes of wildtype (black bar) and wildtype mice pretreated with shGPV-AFP (gray bar) were measured by planimetry 24 h after tMCAO. Results represent mean±SD.

FIG. 3: Soluble GPV has no effect on tail bleeding times. Displayed are tail bleeding times of the indicated mouse lines receiving either vehicle or soluble human GPV (A: shGPV; B: shGPV-AFP). Each symbol represents one animal.

FIG. 4: Treatment with soluble GPV results in reduced surface coverage and thrombus volume on collagen under flow in vitro. A) Human blood was treated with shGPV-AFP and perfused over a collagen-coated surface at a shear rate of 1000 s⁻¹. B) Blood from wildtype mice was incubated with smGPV and perfused over a collagen-coated surface at a shear rate of 1700 s⁻¹. Results are displayed as mean±SD.

DETAILED DESCRIPTION

The present invention relates to a soluble polypeptide comprising a modified glycoprotein V (GPV) lacking a functional transmembrane domain for use in the treatment or prevention of a thrombotic disease in a subject, said treatment or prevention comprising administering to the subject an effective amount of said soluble polypeptide. Preferably, the modified GPV is a truncated GPV.

The term “soluble” as used herein refers to a polypeptide that is not bound to a cell membrane. In particular, a soluble polypeptide is not integrated into a cell membrane via a transmembrane domain and/or it is incapable of being integrated into a cell membrane via a transmembrane domain. Typically, the soluble polypeptide lacks a functional transmembrane domain. Preferably, soluble polypeptides are soluble in water or a buffer, such as PBS.

Glycoprotein V

The term “Glycoprotein V” or “GPV”, as used herein, denotes a protein having a sequence identity of at least 50% to the amino acid sequence as shown in SEQ ID NO:3. Preferably, the GPV has an amino acid identity of at least 60%, or at least 70%, or at least 80%, or at least 90%, or at least 95% to the amino acid sequence as shown in SEQ ID NO:3. In accordance with the present invention, a sequence being evaluated (the “Compared Sequence”) has a certain “percent identity with,” or is a certain “percent identical to” a claimed or described sequence (the “Reference Sequence”) after alignment of the two sequences. The “Percent Identity” is determined according to the following formula:

Percent Identity=100[1−(C/R)]

In this formula, C is the number of differences between the Reference Sequence and the Compared Sequence over the length of alignment between the two sequences wherein (i) each base in the Reference Sequence that does not have a corresponding aligned base in the Compared Sequence, and (ii) each gap in the Reference Sequence, and (iii) each aligned base in the Reference Sequence that is different from an aligned base in the Compared Sequence constitutes a difference. R is the number of bases of the Reference Sequence over the length of the alignment with the Compared Sequence with any gap created in the Reference Sequence also being counted as a base.

If an alignment exists between the Compared Sequence and the Reference Sequence for which the Percent Identity (calculated as above) is about equal to, or greater than, a specified minimum, the Compared Sequence has that specified minimum Percent Identity even if alignments may exist elsewhere in the sequence that show a lower Percent Identity than that specified.

In a preferred embodiment, the length of aligned sequence for comparison purposes is at least 30%, preferably at least 40%, more preferably at least 50%, even more preferably at least 60%, and even more preferably at least 70%, 80%, or 90% of the length of the Reference Sequence.

The comparison of sequences and determination of percent identity (and percent similarity) between two amino acid sequences can be accomplished using any suitable program, e.g. the program “BLAST 2 SEQUENCES (blastp)” (Tatusova et al. FEMS Microbiol. Lett. 1999. 174: 247-250) with the following parameters: Matrix BLOSUM62; Open gap 11 and extension gap 1 penalties; gap x_dropoff50; expect 10.0 word size 3; Filter: none. According to the present invention, the sequence comparison covers at least 40 amino acids, preferably at least 80 amino acids, more preferably at least 100 amino acids, and most preferably at least 120 amino acids.

Typically, the GPV is platelet GPV, and the modified GPV is modified platelet GPV.

Native (i.e. non-modified) GPV comprises a functional transmembrane domain, i.e. it comprises an amino acid sequence capable of conferring integration into a cell membrane (e.g. a plasma membrane) during expression.

The native GPV is a naturally occurring GPV. Preferably, the native GPV is of mammalian origin. In one embodiment, the GPV is a human GPV. According to this embodiment, the native GPV preferably comprises or consists of the amino acid sequence as shown in SEQ ID NO:3. In another embodiment, the native GPV is a murine GPV. According to this embodiment, the native GPV preferably comprises or consists of the amino acid sequence as shown in SEQ ID NO:7. The term native GPV as used herein includes, but is not limited to, homologs and orthologs of human GPV represented by SEQ ID NO:2 (with signal peptide) and SEQ ID NO:3 (without signal peptide). Unless indicated otherwise, the term GPV refers to the mature polypeptide lacking the signal peptide.

Most preferably, the native GPV comprises or consists of the amino acid sequence as shown in SEQ ID NO:3.

Modified GPV

The modified GPV in accordance with this invention differs from the native GPV from which it is derived (also referred to as the “parent GPV” or “non-modified GPV”) at least in that the transmembrane domain is no longer functional, due to mutation or any other means. For example, the amino acid sequence representing the transmembrane domain in the modified GPV may have one or more substitutions, deletions and/or insertions relative to the parent GPV. In one embodiment, the amino acid sequence of the modified GPV lacks at least the entire transmembrane domain of the parent GPV. In another embodiment, the modified GPV is a truncated GPV. The transmembrane domain of human GPV extends from amino acids positions 504 to 527 of SEQ ID NO:3. The transmembrane domain of murine GPV extends from amino acids positions 503 to 526 of SEQ ID NO:7.

1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23 or 24 amino acids of the transmembrane domain of the GPV may be deleted or substituted in the modified GPV. In one embodiment, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23 or 24 amino acids of the transmembrane domain of human GPV (amino acids 504 to 527 of SEQ ID NO:3) may be deleted or substituted. In another embodiment, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23 or 24 amino acids of the transmembrane domain of murine GPV (amino acids 503 to 526 of SEQ ID NO:7) may be deleted or substituted.

The modified GPV, preferably the truncated GPV, has antithrombotic activity. Antithrombotic activity can be determined as shown in the experiment described in Example 1 (See also “Mechanical Injury of the Abdominal Aorta” in the “Materials and Methods” section of the Examples). There is antithrombotic activity if the tested compound (e.g. 20 μg) is capable of delaying or preventing arterial occlusive thrombus formation in mice. Preferably, the arterial occlusive thrombus formation is delayed by at least 1 minute, more preferably by at least 5 minutes, most preferably by at least 10 minutes.

Truncated GPV

A truncated GPV consists of a fragment of GPV. The truncation typically is at the C-terminal end of the GPV. The N-terminal end may be truncated, or it may not be truncated.

The fragment of GPV has a length of at least 6 amino acids. Preferably, the length of the GPV fragment is at least 7, at least 8, at least 9, at least 10, at least 15, at least 20, at least 50, at least 100, at least 200, at least 300, or at least 400 amino acids. In certain embodiments, the truncated GPV consists of a fragment of the amino acid sequence as shown in SEQ ID NO:3, wherein said fragment has a minimum length of 6 amino acids, preferably of at least 7, at least 8, at least 9, at least 10, at least 15, at least 20, at least 50, at least 100, at least 200, at least 300, or at least 400 amino acids.

In one embodiment, the truncated GPV has a C-terminal truncation and lacks the complete transmembrane domain of the GPV from which it is derived. In another embodiment, the truncated GPV has a C-terminal truncation and lacks the transmembrane domain to such an extent that the truncated GPV is not membrane-bound.

Preferred truncated GPVs consist of an amino acid sequence selected from the following amino acid sequences, wherein all amino acid positions refer to SEQ ID NO:3 (embodiments 1-71) or SEQ ID NO:7 (embodiments 72-141), respectively, as indicated:

TABLE 1 Embodiment No. from to of SEQ ID NO: 3 1 1 520 2 2 519 3 3 518 4 4 517 5 5 516 6 6 515 7 7 514 8 8 513 9 9 512 10 10 511 11 11 510 12 12 509 13 13 508 14 14 507 15 15 506 16 16 505 17 17 504 18 18 503 19 19 502 20 20 501 21 21 500 22 22 499 23 23 498 24 24 497 25 25 496 26 26 495 27 27 494 28 28 493 29 29 492 30 30 491 31 31 490 32 32 489 33 33 488 34 34 487 35 35 486 36 36 485 37 37 484 38 38 483 39 39 482 40 40 481 41 41 480 42 42 479 43 43 478 44 44 477 45 45 476 46 46 475 47 47 474 48 48 473 49 49 472 50 50 471 51 51 470 52 52 469 53 53 468 54 54 467 55 55 466 56 56 465 57 57 464 58 58 463 59 59 462 60 60 461 61 61 460 62 62 459 63 63 458 64 64 457 65 65 456 66 66 455 67 67 454 68 68 453 69 69 452 70 70 451 71 71 450 of SEQ ID NO: 7 72 1 520 73 2 519 74 3 518 75 4 517 76 5 516 77 6 515 78 7 514 79 8 513 80 9 512 81 10 511 82 11 510 83 12 509 84 13 508 85 14 507 86 15 506 87 16 505 88 17 504 89 18 503 90 19 502 91 20 501 92 21 500 93 22 499 94 23 498 95 24 497 96 25 496 97 26 495 98 27 494 99 28 493 100 29 492 101 30 491 102 31 490 103 32 489 104 33 488 105 34 487 106 35 486 107 36 485 108 37 484 109 38 483 110 39 482 111 40 481 112 41 480 113 42 479 114 43 478 115 44 477 116 45 476 117 46 475 118 47 474 119 48 473 120 49 472 121 50 471 122 51 470 123 52 469 124 53 468 125 54 467 126 55 466 127 56 465 128 57 464 129 58 463 130 59 462 131 60 461 132 61 460 133 62 459 134 63 458 135 64 457 136 65 456 137 66 455 138 67 454 139 68 453 140 69 452 141 70 451 142 71 450

The upper and lower limits of the amino acid sequences of above embodiments can be combined with each other.

In particularly, preferred embodiments of the truncated GPV consists of amino acids 1-516 of SEQ ID NO:3, or of amino acids 1-502 of SEQ ID NO:7.

In other embodiments, the truncated GPV comprises or consist of the following sequences.

TABLE 2 The truncated GPV comprises or consists of Embodiment No. the following amino acids of SEQ ID NO: 3 143  1-15 144 16-30 145 31-45 146 46-60 147 61-75 148 76-90 149  91-105 150 106-120 151 121-135 152 136-150 153 151-165 154 166-180 155 181-195 156 196-205 157 211-225 158 226-240 159 241-255 160 256-270 161 271-285 162 286-300 163 301-315 164 316-330 165 331-345 166 346-360 167 361-365 168 376-390 169 391-405 170 406-420 171 421-435 172 436-450 173 451-465 174 466-480 175 481-500

In a specific embodiment of the present invention the soluble polypeptide for use as described herein comprises or consists of the amino acid sequence as shown in SEQ ID NO:10.

In another specific embodiment the soluble polypeptide of the invention is a non-naturally occurring polypeptide. In yet another specific embodiment the soluble polypeptide of the invention does not consist of the amino acid sequence as shown in SEQ ID NO:10. In yet another specific embodiment the soluble polypeptide of the invention is a non-naturally occurring polypeptide and does not consist of the amino acid sequence as shown in SEQ ID NO:10.

Further Components of the Polypeptide

The soluble polypeptide of the invention may comprise additional amino acids other than those derived from GPV or other half-life extending moieties.

In one embodiment of the invention, the half-life of the soluble polypeptide of the invention is extended by chemical modification, e.g. attachment, either directly or via a linker, of a half-life extending moiety such as polyethylene glycol (PEGylation), glycosylated PEG, hydroxyl ethyl starch (HESylation), polysialic acids, elastin-like polypeptides, heparosan polymers or hyaluronic acid. In another embodiment, the soluble polypeptide, preferably the modified GPV, is conjugated to a half-life extending protein (HLEP) such as albumin via a chemical linker. The principle of this conjugation technology has been described in an exemplary manner by Conjuchem LLC (see, e.g. U.S. Pat. No. 7,256,253).

In another embodiment of the invention, the soluble polypeptide comprises a heterologous amino acid sequence, i.e. heterologous to the respective GPV used, which is fused to said GPV either directly or via a linker.

Heterologous sequences may be tag sequences which are recognized by antibodies or other molecules having high affinity to the tag. Examples include, but are not limited to, poly-histidine tags, FLAG tag, myc-tag, GST tag, etc. Tag sequences usually facilitate purification of the polypeptide upon expression in host cells.

In a preferred embodiment, the soluble polypeptide further comprises a half-life extending protein (HLEP). Preferably, the HLEP is an albumin or a fragment thereof. The N-terminus of the albumin may be fused to the C-terminus of the modified GPV. One or more HLEPs may be fused to the N- or C-terminal part of modified GPV provided that they do not interfere with or abolish the anti-thrombotic activity of the modified GPV.

In one embodiment the polypeptide has the following structure:

mGPV-L1-H,  [formula 1]

wherein mGPV is the modified GPV, L1 is a chemical bond or a linker sequence, and H is a HLEP.

L1 may be a chemical bond or a linker sequence consisting of one or more amino acids, e.g. of 1 to 50, 1 to 30, 1 to 20, 1 to 15, 1 to 10, 1 to 5 or 1 to 3 (e.g. 1, 2 or 3) amino acids and which may be equal or different from each other. Usually, the linker sequences are not present at the corresponding position in the wild-type GPV. Examples of suitable amino acids present in L1 include Gly and Ser. The linker should be non-immunogenic and may be a non-cleavable or cleavable linker. Non-cleavable linkers may be comprised of alternating glycine and serine residues as exemplified in WO2007/090584. In another embodiment of the invention, the peptidic linker between the modified GPV moiety and the albumin moiety consists of peptide sequences, which serve as natural interdomain linkers in human proteins. Preferably such peptide sequences in their natural environment are located close to the protein surface and are accessible to the immune system so that one can assume a natural tolerance against this sequence. Examples are given in WO2007/090584. Cleavable linker sequences are described, e.g. in WO 2013/120939 A1.

Preferred HLEP sequences are described below. Likewise encompassed by the invention are fusions to the exact “N-terminal amino acid” of the respective HLEP, or fusions to the “N-terminal part” of the respective HLEP, which includes N-terminal deletions of one or more amino acids of the HLEP. The polypeptide may comprise more than one HLEP sequence, e.g. two or three HLEP sequences. These multiple HLEP sequences may be fused to the C-terminal part of modified GPV in tandem, e.g. as successive repeats.

Half-Life Extending Polypeptides (HLEPs)

Preferably, the half-life extending moiety is a half-life extending polypeptide (HLEP), more preferably HLEP is selected from albumin or fragments thereof, immunoglobulin constant region and fragments thereof, e.g. the Fc fragment, solvated random chains with large hydrodynamic volume (e.g. XTEN (Schellenberger et al. Nature Biotechnol. 2009. 27: 1186-1190), homo-amino acid repeats (HAP) or proline-alanine-serine repeats (PAS)), afamin, alpha-fetoprotein, Vitamin D binding protein, transferrin or variants thereof, carboxyl-terminal peptide (CTP) of human chorionic gonadotropin-R subunit, polypeptides or lipids capable of binding under physiological conditions to albumin or immunoglobulin constant region.

A “half-life extending polypeptide” as used herein is preferably selected from the group consisting of albumin, a member of the albumin-family, the constant region of immunoglobulin G and fragments thereof, region and polypeptides capable of binding under physiological conditions to albumin, to members of the albumin family as well as to fragments of an immunoglobulin constant region. It may be a full-length half-life-extending protein described herein (e.g. albumin, a member of the albumin-family or the constant region of immunoglobulin G) or one or more fragments thereof that are capable of stabilizing or prolonging the therapeutic activity or the biological activity of the modified GPV. Such fragments may be of 10 or more amino acids in length or may include at least about 15, at least about 20, at least about 25, at least about 30, at least about 50, at least about 100, or more contiguous amino acids from the HLEP sequence or may include part or all of specific domains of the respective HLEP, as long as the HLEP fragment provides a functional half-life extension of at least 25% compared to the respective polypeptide without the HLEP.

The HLEP fragment of the proposed coagulation factor insertion constructs of the invention may be a variant of a normal HLEP. The term “variants” includes insertions, deletions and substitutions, either conservative or non-conservative, where such changes do not substantially alter the active site, or active domain which confers the biological activities of the modified GPV.

In particular, the proposed modified GPV-HLEP fusion constructs of the invention may include naturally occurring polymorphic variants of HLEPs and fragments of HLEPs. The HLEP may be derived from any vertebrate, especially any mammal, for example human, monkey, cow, sheep, or pig. Non-mammalian HLEPs include, but are not limited to, hen and salmon.

Albumin as HLEP

The terms, “human serum albumin” (HSA) and “human albumin” (HA) and “albumin” (ALB) are used interchangeably in this application. The terms “albumin” and “serum albumin” are broader, and encompass human serum albumin (and fragments and variants thereof) as well as albumin from other species (and fragments and variants thereof).

As used herein, “albumin” refers collectively to albumin polypeptide or amino acid sequence, or an albumin fragment or variant, having one or more functional activities (e.g., biological activities) of albumin. In particular, “albumin” refers to human albumin or fragments thereof, especially the mature form of human albumin or albumin from other vertebrates or fragments thereof, or analogs or variants of these molecules or fragments thereof.

In particular, the proposed modified GPV fusion constructs of the invention may include naturally occurring polymorphic variants of human albumin and fragments of human albumin.

Generally speaking, an albumin fragment or variant will be at least 10, preferably at least 40, most preferably more than 70 amino acids long.

The albumin fragment of the proposed modified GPV fusion constructs of the invention may comprise at least one subdomain or domain of HA or conservative modifications thereof.

Immunoglobulins as HLEPs

In a preferred embodiment the soluble polypeptide of the invention comprises or consists of the amino acid sequence as shown in SEQ ID NO:9.

Immunoglobulins as HLEPs

Immunoglobulin G (IgG) constant regions (Fc) are known in the art to increase the half-life of therapeutic proteins (Dumont J A, et al. BioDrugs. 2006; 20: 151-160). The IgG constant region of the heavy chain consists of 3 domains (CH1-CH3) and a hinge region. The immunoglobulin sequence may be derived from any mammal, or from subclasses IgG1, IgG2, IgG3 or IgG4, respectively. IgG and IgG fragments without an antigen-binding domain may also be used as HLEPs. The therapeutic polypeptide fragment is connected to the IgG or the IgG fragments preferably via the hinge region of the antibody or a peptidic linker, which may even be cleavable. Several patents and patent applications describe the fusion of therapeutic proteins to immunoglobulin constant regions to enhance the therapeutic proteins in vivo half-lives. US 2004/0087778 and WO 2005/001025 describe fusion proteins of Fc domains or at least fragments of immunoglobulin constant regions with biologically active peptides that increase the half-life of the peptide, which otherwise would be quickly eliminated in vivo. Fc-IFN-β fusion proteins were described that achieved enhanced biological activity, prolonged circulating half-life and greater solubility (WO 2006/000448). Fc-EPO proteins with a prolonged serum half-life and increased in vivo potency were disclosed (WO 2005/063808) as well as Fc fusions with G-CSF (WO 2003/076567), glucagon-like peptide-1 (WO 2005/000892), clotting factors (WO 2004/101740) and interleukin-10 (U.S. Pat. No. 6,403,077), all with half-life extending properties.

In certain embodiments, the Fc fusion protein is monomeric. In other embodiments, the Fc fusion protein is dimeric.

Various HLEPs which can be used in accordance with this invention are described in detail in WO 2013/120939.

Nucleic Acid and Expression

The nucleic acid encoding the polypeptide to be expressed can be prepared according to methods known in the art. Based on the cDNA sequence of human GPV (SEQ ID NO:1) or of murine GPV (SEQ ID NO:5), recombinant DNA encoding the above-mentioned modified GPV constructs can be designed and generated. Further details of the human and mouse sequences are summarized in table 3.

TABLE 3 Details of mouse and human wild-type GPV Sequences Mouse Human Entrez 14729 2814 Ensembl ENSMUSG00000047953 ENSG00000178732 Uniprot Q3TA66 P40197 mRNA RefSeq NM_008148 NM_004488 Protein RefSeq NP_032174 NP_004479 Location Chr 16: 30.23 - 30.23 Mb Chr 3: 195.6 - 195.6 Mb Molecular Mass 63251 60828 [Da]

Constructs in which the cDNA contains the entire open reading frame inserted in the correct orientation into an expression plasmid may be used for protein expression. Typical expression vectors contain promoters that direct the synthesis of large amounts of mRNA corresponding to the inserted nucleic acid in the plasmid-bearing cells. They may also include an origin of replication sequence allowing for their autonomous replication within the host organism, and sequences that increase the efficiency with which the synthesized mRNA is translated. Stable long-term vectors may be maintained as freely replicating entities by using regulatory elements of, for example, viruses (e.g. the OriP sequences from the Epstein Barr Virus genome). Cell lines may also be produced that have integrated the vector into the genomic DNA, and in this manner the gene product is produced on a continuous basis.

Typically, the cells to be provided are obtained by introducing the nucleic acid encoding a polypeptide comprising the modified GPV into mammalian host cells.

Host Cells

Any host cell susceptible to cell culture, and to expression of polypeptides, preferably glycosylated polypeptides, may be utilized in accordance with the present invention. In certain embodiments, the host cell is mammalian. Non-limiting examples of mammalian cells that may be used in accordance with the present invention include BALB/c mouse myeloma line (NSO/1, ECACC No: 85110503); human retinoblasts (PER.C6 (CruCell, Leiden, The Netherlands)); monkey kidney CV1 line transformed by SV40 (COS-7, ATCC CRL 1651); human embryonic kidney line (HEK293 or HEK293 cells subcloned for growth in suspension culture, Graham et al., J. Gen Virol., 36:59, 1977); baby hamster kidney cells (BHK, ATCC CCL10); Chinese hamster ovary cells +/−DHFR (CHO, Urlaub and Chasin, Proc. Natl. Acad. Sci. USA, 77:4216, 1980); mouse sertoli cells (TM4, Mather, Biol. Reprod., 23:243 251, 1980); monkey kidney cells (CV1 ATCC CCL 70); African green monkey kidney cells (VERO-76, ATCC CRL-1 587); human cervical carcinoma cells (HeLa, ATCC CCL 2); canine kidney cells (MDCK, ATCC CCL 34); buffalo rat liver cells (BRL 3A, ATCC CRL 1442); human lung cells (W138, ATCC CCL 75); human liver cells (HepG2, HB 8065); mouse mammary tumor (MMT 060562, ATCC CCL51); TRI cells (Mather et al., Annals NY. Acad. Sci., 383:44-68, 1982); MRC 5 cells; PS4 cells; human amniocyte cells (CAP); and a human hepatoma line (Hep G2). Preferably, the cell line is a human or a rodent cell line, especially a hamster cell line such as CHO.

Methods suitable for introducing nucleic acids sufficient to achieve expression of a glycoprotein of interest into mammalian host cells are known in the art. See, for example, Gething, et al., Nature. 1981; 293: 620-625; Mantei, et al., Nature. 1979; 281: 40-46; Levinson, et al. EP 117,060; and EP 117,058. For mammalian cells, common methods of introducing genetic material into mammalian cells include the calcium phosphate precipitation method of Graham and van der Erb (Virology. 1978; 52: 456-457) or the Lipofectamine™ (Gibco BRL) Method of Hawley-Nelson (Focus. 1993; 15: 73). General aspects of mammalian host cell system transfections have been described by Axel in U.S. Pat. No. 4,399,216. For various techniques for introducing genetic material into mammalian cells, see Keown et al. (Methods in Enzymology, 1989), Keown et al. (Methods in Enzymology. 1990; 185: 527-537), and Mansour et al. (Nature, 1988; 336: 348-352).

The basal medium chosen for culturing the host cell line is not critical to the present invention and may be any one of, or combination of, those known to the art which are suitable for culturing mammalian cells. Media such as Dulbecco's Modified Eagle Medium, Ham's F-12 Medium, Eagle's Minimal Essential Medium and RPMI-1640 Medium and the like are commercially available. The addition of growth factors such as recombinant insulin is optional. In one embodiment, the production medium is free of animal-derived components. In a preferred embodiment, the medium is “protein-free” in the sense that it is either completely free of any protein or at least free of any protein that is not recombinantly produced. Human serum albumin may be used as a serum-free culture supplement for the production of the glycoprotein. Optionally, the medium contains a protease inhibitor, such as a serine protease inhibitor, which is suitable for tissue culture and which is of synthetic or vegetable origin.

Generally, the present invention may be used with any cell culture method that is amenable to the expression of glycoproteins. For example, cells may be grown in batch or fed-batch cultures, where the culture is terminated after sufficient expression of the glycoprotein, after which the expressed glycoprotein is harvested. Preferably, cells may be grown in continuous cultures (e.g. perfusion cultures), where fresh medium is periodically or continuously added to the culture, and the expressed glycoprotein is harvested periodically or continuously. The culture can be of any conventional type of culture, such as batch, fed-batch or continuous, but is preferably continuous. Suitable continuous cultures include perfusion culture.

One of ordinary skill in the art will be able to tailor specific cell culture conditions in order to optimize certain characteristics of the cell culture including but not limited to growth rate, cell viability, final cell density of the cell culture, final concentration of detrimental metabolic byproducts such as lactate and ammonium, titer of the expressed glycoprotein, extent and composition of the oligosaccharide side chains or any combination of these or other conditions deemed important by the practitioner.

Isolation of the Expressed Soluble Polypeptide

In general, it will typically be desirable to isolate and/or purify glycoproteins expressed according to the present invention. In certain embodiments, the expressed glycoprotein is secreted into the medium and thus cells and other solids may be removed, as by centrifugation or filtering for example, as a first step in the purification process.

The expressed glycoprotein may be isolated and purified by standard methods including, but not limited to, chromatography (e.g., ion exchange, affinity, size exclusion, and hydroxyapatite chromatography), gel filtration, centrifugation, or differential solubility, ethanol precipitation and/or by any other available technique for the purification of proteins (see, e.g. Scopes, Protein Purification Principles and Practice 2nd Edition, Springer-Verlag, New York, 1987; Higgins S J and Hames B D (eds.), Protein Expression: A Practical Approach, Oxford Univ Press, 1999; and Deutscher M P, Simon M I, Abelson J N (eds.), Guide to Protein Purification: Methods in Enzymology (Methods in Enzymology Series, Vol. 182), Academic Press, 1997, each of which is incorporated herein by reference). For immunoaffinity chromatography in particular, the glycoprotein may be isolated by binding it to an affinity column comprising antibodies that were raised against that glycoprotein and were affixed to a stationary support. Alternatively, affinity tags such as an influenza coat sequence, poly-histidine, or glutathione-S-transferase can be attached to the glycoprotein by standard recombinant techniques to allow for easy purification by passage over the appropriate affinity column. If the soluble GPV to be purified comprises a HLEP, antibodies directed against the HLEP, or other compounds capable of binding to the HLEP can be affixed to an affinity column so as to perform affinity chromatography. Protease inhibitors such as phenyl methyl sulfonyl fluoride (PMSF), leupeptin, pepstatin or aprotinin may be added at any or all stages in order to reduce or eliminate degradation of the glycoprotein during the purification process. Protease inhibitors are particularly advantageous when cells must be lysed in order to isolate and purify the expressed glycoprotein. Additionally or alternatively, glycosidase inhibitors may be added at any or all stages in order to reduce or eliminate enzymatic trimming of the covalently attached oligosaccharide chains.

One of ordinary skill in the art will appreciate that the exact purification technique will vary depending on the character of the polypeptide to be purified, the character of the cells from which the polypeptide is expressed, and/or the composition of the medium in which the cells were grown.

Compositions and Kits

Another aspect of the invention is a pharmaceutical composition comprising soluble polypeptide of the invention, and a pharmaceutically acceptable excipient or carrier. The pharmaceutical composition may comprise a soluble polypeptide in an effective amount for treating or preventing a thrombotic disease in a subject. The pharmaceutical composition may comprise about 10 μg-1,000 mg, preferably about 100 μg-500 mg, more preferably 1 mg-100 mg of the soluble polypeptide. The pharmaceutical composition may comprise about 0.01-20,000 μg/ml, preferably about 0.1-1000 μg/ml, more preferably 0.5-500 μg/ml, most preferably about 100 μg/ml of the soluble polypeptide. The pharmaceutical composition may further comprise a pharmaceutically acceptable carrier or diluent. Carriers and diluents suitable in the pharmaceutical composition are well known in the art.

Therapeutic formulations of the glycoproteins of the invention suitable in the methods described herein can be prepared for storage as lyophilized formulations or aqueous solutions by mixing the glycoprotein having the desired degree of purity with optional pharmaceutically-acceptable carriers, excipients or stabilizers typically employed in the art (all of which are referred to herein as “carriers”), i.e., buffering agents, stabilizing agents, preservatives, isotonifiers, non-ionic detergents, antioxidants, and other miscellaneous additives, see, Remington's Pharmaceutical Sciences, 16th edition (Osol, ed.) 1980. Such additives must be nontoxic to the recipients at the dosages and concentrations employed.

Buffering agents help to maintain the pH in the range which approximates physiological conditions. They can present at concentration ranging from about 2 mM to about 50 mM. Suitable buffering agents include both organic and inorganic acids and salts thereof such as citrate buffers (e.g. monosodium citrate-disodium citrate mixture, citric acid-trisodium citrate mixture, citric acid-monosodium citrate mixture, etc.), succinate buffers (e.g. succinic acid-monosodium succinate mixture, succinic acid-sodium hydroxide mixture, succinic acid-disodium succinate mixture, etc.), tartrate buffers (e.g. tartaric acid-sodium tartrate mixture, tartaric acid-potassium tartrate mixture, tartaric acid-sodium hydroxide mixture, etc.), fumarate buffers (e.g. fumaric acid-monosodium fumarate mixture, fumaric acid-disodium fumarate mixture, monosodium fumarate-disodium fumarate mixture, etc.), gluconate buffers (e.g. gluconic acid-sodium glyconate mixture, gluconic acid-sodium hydroxide mixture, gluconic acid-potassium glyuconate mixture, etc.), oxalate buffer (e.g., oxalic acid-sodium oxalate mixture, oxalic acid-sodium hydroxide mixture, oxalic acid-potassium oxalate mixture, etc), lactate buffers (e.g. lactic acid-sodium lactate mixture, lactic acid-sodium hydroxide mixture, lactic acid-potassium lactate mixture, etc.) and acetate buffers (e.g. acetic acid-sodium acetate mixture, acetic acid-sodium hydroxide mixture, etc.). Additionally, phosphate buffers, histidine buffers and trimethylamine salts such as Tris can be used.

Preservatives can be added to retard microbial growth, and can be added in amounts ranging from 0.2%-1% (w/v). Suitable preservatives include phenol, benzyl alcohol, meta-cresol, methyl paraben, propyl paraben, octadecyldimethylbenzyl ammonium chloride, benzalconium halides (e.g. chloride, bromide, and iodide), hexamethonium chloride, and alkyl parabens such as methyl or propyl paraben, catechol, resorcinol, cyclohexanol, and 3-pentanol. Isotonicifiers sometimes known as “stabilizers” can be added to ensure isotonicity of liquid compositions and include polyhydric sugar alcohols, preferably trihydric or higher sugar alcohols, such as glycerin, erythritol, arabitol, xylitol, sorbitol and mannitol. Stabilizers refer to a broad category of excipients which can range in function from a bulking agent to an additive which solubilizes the therapeutic agent or helps to prevent denaturation or adherence to the container wall. Typical stabilizers can be polyhydric sugar alcohols (enumerated above); amino acids such as arginine, lysine, glycine, glutamine, asparagine, histidine, alanine, ornithine, L-leucine, 2-phenylalanine, glutamic acid, threonine, etc., organic sugars or sugar alcohols, such as lactose, trehalose, stachyose, mannitol, sorbitol, xylitol, ribitol, myoinisitol, galactitol, glycerol and the like, including cyclitols such as inositol; polyethylene glycol; amino acid polymers; sulfur containing reducing agents, such as urea, glutathione, thioctic acid, sodium thioglycolate, thioglycerol, α-monothioglycerol and sodium thio sulfate; low molecular weight polypeptides (e.g., peptides of 10 residues or fewer); proteins such as human serum albumin, bovine serum albumin, gelatin or immunoglobulins; hydrophylic polymers, such as polyvinylpyrrolidone monosaccharides, such as xylose, mannose, fructose, glucose; disaccharides such as lactose, maltose, sucrose and trisaccacharides such as raffinose; and polysaccharides such as dextran. Stabilizers can be present in the range from 0.1 to 10,000 weights per part of weight active protein.

Non-ionic surfactants or detergents (also known as “wetting agents”) can be added to help solubilize the therapeutic agent as well as to protect the therapeutic protein against agitation-induced aggregation, which also permits the formulation to be exposed to shear surface stressed without causing denaturation of the protein. Suitable non-ionic surfactants include polysorbates (20, 80, etc.), polyoxamers (184, 188, etc.), Pluronic polyols, polyoxyethylene sorbitan monoethers (TWEEN®-20, TWEEN®-80, etc.). Non-ionic surfactants can be present in a range of about 0.05 mg/ml to about 1.0 mg/ml, or in a range of about 0.07 mg/ml to about 0.2 mg/ml.

Additional miscellaneous excipients include bulking agents (e.g. starch), chelating agents (e.g. EDTA), antioxidants (e.g. ascorbic acid, methionine, vitamin E), and cosolvents. The pharmaceutical composition may have a pH of about 5.0-10.0, preferably about 5.6-9.0, more preferably about 6.0-8.8, most preferably about 6.5-8.0. For example, the pH may be about 6.2, 6.5, 6.75, 7.0, or 7.5.

The pharmaceutical compositions of the present invention may be formulated for oral, sublingual, intranasal, intraocular, rectal, transdermal, mucosal, topical or parenteral administration. Parenteral administration may include intradermal, subcutaneous, intramuscular (i.m.), intravenous (i.v.), intraperitoneal (i.p.), intra-arterial, intramedullary, intracardiac, intraarticular (joint), intrasynovial, intracranial, intraspinal, and intrathecal (spinal fluids) injection or infusion, preferably intraperitoneal (i.p.) injection in mouse and intravenous (i.v.) or subcutaneous (s.c.) in human. Any device suitable for parenteral injection or infusion of drug formulations may be used for such administration. For example, the pharmaceutical composition may be contained in a sterile pre-filled syringe.

Another aspect of the present invention is a pharmaceutical kit comprising (i) a soluble polypeptide as defined hereinabove and (ii) an anticoagulant or antiplatelet drug other than said soluble polypeptide. In one embodiment, the soluble polypeptide and the anticoagulant or antiplatelet drug are contained in separate compositions.

The term “anticoagulant or antiplatelet drug” refers to heparins, direct thrombin inhibitors (DTI), direct or selective Factor Xa inhibitors (xaban) and vitamin K antagonists (VKA). Thus, “anticoagulant or antiplatelet drugs” can include natural occurring or synthetic heparins. The term “anticoagulant or antiplatelet drug” also meant to include substances that prevent coagulation of blood by inhibiting directly or selective thrombin or Factor Xa. In another embodiment, the anticoagulant substance is a vitamin K antagonist.

In some embodiments the anticoagulant or antiplatelet drug is selected from

-   -   (i) a heparin, in particular a unfractionated heparin (UFH) or a         low-molecular-weight heparin (LMWH),     -   (ii) a direct thrombin inhibitor (DTI), in particular         dabigatran, melagatran, argatroban, hirudin, lepirudin,         bivalirudin, ximelagatran or desirudin (Di Nisio et al. N Engl J         Med. 2005; 353: 1028-40),     -   (iii) a direct or selective Factor Xa inhibitor (xaban), in         particular rivaroxaban (Eriksson et al., Circulation. 114:         2374-81), apixaban (Arterioscler. Thromb. Vasc. Biol. 27:         1238-47), betrixaban, edoxaban, otamixaban (Cohen et al.,         Circulation 115: 2642-51) or fondaparinux (Peters et al., Eur.         Heart J. 29: 324-31) and,     -   (iv) a vitamin K antagonist (VKA), in particular phenprocoumon,         acenocoumarol or warfarin and related         4-hydroxycoumarin-containing molecules, coumatetralyl,         dicoumarol, ethyl biscoumacetate, clorindione, diphenandione,         phenandione or tioclomarol (see e.g. Ansell et al. 2008,         “Pharmacology and management of the vitamin K antagonists”,         American College of Chest Physicians Evidence-Based Clinical         Practice Guidelines (8th Edition). Chest 133 (6 Suppl):         160S-198S).

Another aspect of the present invention is a pharmaceutical kit comprising (i) a soluble polypeptide as defined hereinabove and (ii) an antiplatelet or anticoagulant drug other than said soluble polypeptide, for simultaneous, separate or sequential use in the treatment of a thrombotic disease.

Treatment of Thrombotic Disease

The soluble polypeptide of the invention can be used for treating or preventing thrombotic diseases.

A “thrombotic disorder” or “thrombotic disease” used herein is any disorder or disease characterized by the formation of a thrombus (blood clot) that obstructs or decreases blood flow. The thrombus may remain local to where it formed, or it may detach to occlude blood flow downstream (thromboembolism). In some embodiments, a thrombosis may occur in a vein (venous thrombosis) or in an artery (arterial thrombosis) anywhere in the body, including the heart and brain. When the thrombosis occurs in the coronary circulation, it is referred to as a coronary thrombosis. When the thrombosis occurs in the cerebral circulation, it is referred to as a cerebral thrombosis.

A thrombotic disorder can include a venous, arterial, or capillary thrombosis, thrombus formation in the heart, chronic and/or acute thromboembolism (e.g. pulmonary embolism, cerebral thromboembolism following atrial fibrillation-induced thrombus formation (e.g. stroke prevention in atrial fibrillation (SPAF)), thrombus formation as a result of contacting the blood of a human or animal subject with an artificial surface (e.g. in patients with valve replacements, in particular a mechanical heart valve, stents, percutaneous coronary intervention (PCI), extracorporeal membrane oxygenation (ECMO), or undergoing cardiopulmonary bypass surgery (CPB surgery)). The thrombus can cause or increase the risk of a stroke, acute ischemic stroke, myocardial infarction, unstable angina, deep vein thrombosis (DVT), portal vein thrombosis, thromboembolism, renal vein thrombosis, jugular vein thrombosis, cerebral venous sinus thrombosis, Budd-Chiari syndrome, Paget-Schroetter diseases, or silent brain ischemia (SBI). A thrombotic disease in accordance with this invention may further include pulmonary embolism, atherosclerosis, factor V Leiden, antithrombin III deficiency, protein C deficiency, protein S deficiency, prothrombin gene mutation (G20210A), hyperhomocysteinemia, antiphospholipid antibody syndrome, anticardiolipin antibody, thrombosis syndrome, lupus anticoagulant syndrome, malignancy, major surgery, immobilization, oral contraceptive use, thalidomide use, especially in combination with dexamethasone, heparin-induced thrombocytopenia, pregnancy, myeloproliferative disorders, inflammatory bowel disease, nephrotic syndrome, paroxysmal nocturnal hemoglobinuria, hyperviscosity syndrome, Waldenstrom's macroglobulinemia, and trauma. The term thrombotic disease also refers to thrombosis induced by cancer, e.g. multiple myeloma and other hematologic cancers, adenocarcinoma, cancer of the pancreas, stomach, ovaries, prostate, colon, lung, brain, breast, kidney, skin, cervix, and ear-nose-throat cancer.

The term “thrombotic disease” particularly includes thrombo-inflammatory conditions. Thrombo-inflammation means disease states, where prothrombotic and pro-inflammatory cascades act in concert and are mechanistically linked to promote disease progression and organ damage. Thrombo-inflammatory disease states include conditions of post-ischemic organ damage, such as ischemia/reperfusion injury (I/R-injury) of the brain (in acute ischemic stroke), lung, liver, colon, myocardium, or skeletal muscle but also systemic inflammatory conditions such as sepsis or septic shock.

Preferably, the thrombotic disease is selected from the group consisting of thrombo-inflammatory conditions, venous thrombosis, arterial thrombosis, capillary thrombosis, portal vein thrombosis, renal vein thrombosis, jugular vein thrombosis, cerebral venous sinus thrombosis, thrombus formation during or after contacting blood with an artificial surface, in particular extracorporeal membrane oxygenation (ECMO), atherosclerosis, arthritis, coagulopathy, deep venous thrombosis (DVT), disseminated intravascular coagulopathy (DIC), a chronic or acute thromboembolism, pulmonary thromboembolism, Budd-Chiari syndrome, Paget-Schroetter diseases, stroke and myocardial infraction.

Determination of the effective dosage, total number of doses, and length of treatment with a soluble polypeptide of the invention is well within the capabilities of those skilled in the art, and can be determined using a standard dose escalation study. The dosage of a soluble polypeptide of the invention to be administered will vary according to the particular soluble polypeptide, the subject, and the nature and severity of the disease, the physical condition of the subject, the therapeutic regimen (e.g. whether a second therapeutic agent is used), and the selected route of administration; the appropriate dosage can be readily determined by a person skilled in the art.

The dosing schedule can vary from once a month to daily depending on a number of clinical factors, including the particular type of disease, severity of disease, and the patient's sensitivity to the soluble polypeptide of the invention. In specific embodiments, a soluble polypeptide of the invention is administered, twice weekly, every 5 days, once weekly, every 10 days, every two weeks, every three weeks, every four weeks or once a month, or in any range between any two of the foregoing values, for example from every week to every month, from every 10 days to every two weeks, or from two to three times a week, etc.

It will be recognized by one of skill in the art that the optimal quantity and spacing of individual dosages of a soluble polypeptide of the invention will be determined by the nature and extent of the condition being treated, the form, route and site of administration, and the age and condition of the particular subject being treated, and that a physician will ultimately determine appropriate dosages to be used. This dosage can be repeated as often as appropriate. If side effects develop the amount and/or frequency of the dosage can be altered or reduced, in accordance with normal clinical practice.

TABLE 4 Overview of the sequences shown in the sequence listing SEQ ID NO: Description 1 cDNA encoding human GPV 2 Amino acid sequence encoded by SEQ ID NO: 1; amino acids 1-16 represent the signal peptide 3 Amino acid sequence of human GPV without signal peptide 4 Amino acid sequence of soluble human GPV with poly-His tag (without signal peptide) 5 cDNA encoding murine GPV 6 Amino acid sequence encoded by SEQ ID NO: 5; amino acids 1-16 represent the signal peptide 7 Amino acid sequence of murine GPV without signal peptide 8 Amino acid sequence of soluble murine GPV with Flag-tag (without signal peptide) 9 Amino acid sequence of soluble human GPV fused to albumin via linker (without signal peptide) 10 Amino acid sequence of naturally occurring thrombin cleavage product of human GPV

EXAMPLES Results Example 1: Soluble GPV has an Antithrombotic Effect

In order to investigate a potential effect of sGPV on in vivo thrombus formation in a model of mechanical injury of the abdominal aorta, 20 μg human sGPV (shGPV) were injected intravenously into WT mice directly before the experiment. Within 8 min after the aortic injury, blood flow stopped due to occlusive thrombus formation in PBS-injected control mice (FIG. 1). Pretreatment with sGPV protected WT mice from arterial occlusive thrombus formation indicating that the shGPV has an antithrombotic effect (FIG. 1).

Example 2: Soluble Human GPV Protects from Ischemic Stroke

To assess the role of soluble GPV in brain infarction after focal cerebral ischemia, mice were subjected to 60-minute transient middle cerebral artery occlusion (tMCAO), and infarct volume was assessed after 24 hours. Strikingly, the infarct volumes in wildtype mice treated with shGPV-AFP were significantly reduced compared with wild-type mice (FIG. 2). Thus, pre-treatment with soluble human GPV provides protection against cerebral infarct progression.

Example 3: Soluble Human GPV has No Effect on Tail Bleeding Times

To assess the role of soluble GPV on hemostasis, mice treated either with vehicle or 20 μg soluble human GPV (shGPV) were subjected to the tail bleeding time assay. A 2-mm segment of the tail tip was removed with a scalpel. Tail bleeding was monitored by gently absorbing blood with filter paper at 20 s intervals without directly contacting the wound site. When no blood was observed on the paper, bleeding was determined to have ceased. (FIG. 3). These data demonstrate, that shGPV doses, which exert anti-thrombotic effects (FIG. 1) do not affect hemostasis indicating that shGPV is a safe anti-thrombotic agent.

Example 4: Adhesion to Collagen Under Flow In Vitro

To assess the role of soluble GPV on thrombus formation on collagen under flow in an in vitro assay, anticoagulated whole blood was incubated with 20 μg soluble GPV for 5 min and perfused over a collagen-coated surface. Human blood pretreated with shGPV-AFP (A) or wildtype blood pretreated with soluble murine GPV (B) exhibited a significantly reduced surface coverage and reduced thrombus formation. Thus, in vitro flow adhesion assay models the in vivo conditions too a large extent and reproduces the in vivo phenotype.

Materials and Methods for Examples 1-4 Mice

Animal studies were approved by the district government of Lower Franconia (Bezirksregierung Unterfranken).

Soluble GPV

1. Soluble Human GPV (shGPV)

Soluble human GPV (aa 1-518 of mature human GPV) was recombinantly expressed in baculovirus-transfected insect cells, purified using a standard nitrilotriacetic acid (Ni-NTA) column and solved in PBS buffer. Purity was checked using standard SDS PAGE.

Amino acid sequence of mature shGPV (signal peptide not shown):

(SEQ ID NO: 4) QPFPCPPACKCVFRDAAQCSGGDVARISALGLPTNLTHILLFGMGRGVLQ SQSFSGMTVLQRLMISDSHISAVAPGTFSDLIKLKTLRLSRNKITHLPGA LLDKMVLLEQLFLDHNALRGIDQNMFQKLVNLQELALNQNQLDFLPASLF TNLENLKLLDLSGNNLTHLPKGLLGAQAKLERLLLHSNRLVSLDSGLLNS LGALTELQFHRNHIRSIAPGAFDRLPNLSSLTLSRNHLAFLPSALFLHSH NLTLLTLFENPLAELPGVLFGEMGGLQELWLNRTQLRTLPAAAFRNLSRL RYLGVTLSPRLSALPQGAFQGLGELQVLALHSNGLTALPDGLLRGLGKLR QVSLRRNRLRALPRALFRNLSSLESVQLDHNQLETLPGDVFGALPRLTEV LLGHNSWRCDCGLGPFLGWLRQHLGLVGGEEPPRCAGPGAHAGLPLWALP GGDAECPGPRGPPPRPAADSSSEAPVHPALAPNSSEPWVWAQPVTTGKGQ DHSPFWGFYFLLLAVQAHHHHHHHHHH (Italics: poly-His tag) 2. Soluble Human GPV Fused to Albumin (shGPV-AFP)

The shGPV-AFP was expressed in CHO K1 cells and produced in a perfusion fermenter system. The cell free harvest was 30 fold concentrated using a TFF system (e.g. Centramate 500 S Pall) with a 30 kD membrane (e.g Centramate 05030T12). That concentrate was spiked with NaCl and EDTA to a final concentration of 0.75 mol/L NaCl and 5 mmol/L EDTA and loaded overnight on a CaptureSelect Human Albumin column (Lifetechnologies) which was preequlibrated with 20 mM Tris buffer pH 7.4. After washing the column with equilibration buffer shGPV-AFP was eluted with 20 mM Tris plus 2 M MgCl pH 7.4 buffer. The eluate was than concentrated and dialyzed against 50 mM Tris+150 mM NaCl pH7.4 using Ultra Centrifugal Filters with a 30 kD cut off (e.g. Amicon Ref. UFC903024).

Amino acid sequence of mature shGPV-AFP (signal peptide not shown):

(SEQ ID NO: 9) QPFPCPPACKCVFRDAAQCSGGDVARISALGLPTNLTHILLFGMGRGVLQ SQSFSGMTVLQRLMISDSHISAVAPGTFSDLIKLKTLRLSRNKITHLPGA LLDKMVLLEQLFLDHNALRGIDQNMFQKLVNLQELALNQNQLDFLPASLF TNLENLKLLDLSGNNLTHLPKGLLGAQAKLERLLLHSNRLVSLDSGLLNS LGALTELQFHRNHIRSIAPGAFDRLPNLSSLTLSRNHLAFLPSALFLHSH NLTLLTLFENPLAELPGVLFGEMGGLQELWLNRTQLRTLPAAAFRNLSRL RYLGVTLSPRLSALPQGAFQGLGELQVLALHSNGLTALPDGLLRGLGKLR QVSLRRNRLRALPRALFRNLSSLESVQLDHNQLETLPGDVFGALPRLTEV LLGHNSWRCDCGLGPFLGWLRQHLGLVGGEEPPRCAGPGAHAGLPLWALP GGDAECPGPRAVGSGGSGGSGGSGGSGGSGGSGGSGGSGGSGS DAHKSEV AHRFKDLGEENFKALVLIAFAQYLQQCPFEDHVKLVNEVTEFAKTCVA DESAENCDKSLHTLFGDKLCTVATLRETYGEMADCCAKQEPERNECFL QHKDDNPNLPRLVRPEVDVMCTAFHDNEETFLKKYLYEIARRHPYFYA PELLFFAKRYKAAFTECCQAADKAACLLPKLDELRDEGKASSAKQRLK CASLQKFGERAFKAWAVARLSQRFPKAEFAEVSKLVTDLTKVHTECCH GDLLECADDRADLAKYICENQDSISSKLKECCEKPLLEKSHCIAEVEN DEMPADLPSLAADFVESKDVCKNYAEAKDVFLGMFLYEYARRHPDYSV VLLLRLAKTYETTLEKCCAAADPHECYAKVFDEFKPLVEEPQNLIKQN CELFEQLGEYKFQNALLVRYTKKVPQVSTPTLVEVSRNLGKVGSKCCK HPEAKRMPCAEDYLSVVLNQLCVLHEKTPVSDRVTKCCTESLVNRRPC FSALEVDETYVPKEFNAETFTFHADICTLSEKERQIKKQTALVELVKH KPKATKEQLKAVMDDFAAFVEKCCKADDKETCFAEEGKKLVAASQAAL GL (Underlined: thrombin cleavage site and GGS Linker; Italics: human albumin sequence) 3. Soluble Murine GPV (smGPV)

Soluble murine GPV (aa 1-519 of mature murine GPV) was recombinantly expressed in CHO cells, purified using an anti-Flag column and solved in PBS buffer. Purity was checked using standard SDS PAGE.

Amino acid sequence of mature smGPV (signal peptide not shown):

(SEQ ID NO: 8) QPFPCPKTCKCVVRDAAQCSGGSVAHIAELGLPTNLTHILLFRMDQGILR NHSFSGMTVLQRQMLSDSHISAIDPGTFNDLVKLKTLRLTRNKISRLPRA ILDKMVLLEQLFLDHNALRDLDQNLFQQLRNLQELGLNQNQLSFLPANLF SSLRELKLLDLSRNNLTHLPKGLLGAQVKLEKLLLYSNQLTSVDSGLLSN LGALTELRLERNHLRSVAPGAFDRLGNLSSLTLSGNLLESLPPALFLHVS SVSRLTLFENPLEELPDVLFGEMAGLRELWLNGTHLSTLPAAAFRNLSGL QTLGLTRNPRLSALPRGVFQGLRELRVLGLHTNALAELRDDALRGLGHLR QVSLRHNRLRALPRTLFRNLSSLESVQLEHNQLETLPGDVFAALPQLTQV LLGHNPWLCDCGLWRFLQWLRHHPDILGRDEPPQCRGPEPRASLSFWELL QGDPWCPDPRSLPLDPPTENALEAPVPSWLPNSWQSQTWAQLVARGESPN NRLECGRNPAFLYKVVLEMDYKDDDDK (Italics: Flag tag)

Mechanical-Injury of the Abdominal Aorta

To open the abdominal cavity of anesthetized mice (10-16 weeks of age), a longitudinal midline incision was performed and the abdominal aorta was exposed. A Doppler ultrasonic flow probe (Transonic Systems, Maastricht, Netherlands) was placed around the aorta and thrombosis was induced by a mechanical injury with a single firm compression (15 s) of a forceps upstream of the flow probe. Blood flow was monitored until complete occlusion occurred or 30 min had elapsed.

Transient Middle Cerebral Artery Occlusion (tMCAO)

Focal cerebral ischemia was induced in 8-to-12-week-old mice by a transient middle cerebral artery occlusion (tMCAO). Inhalation anesthesia was induced by 2% isoflurane in a 70% N₂/30% O₂ mixture and a servo-controlled heating device was used to record and maintain body temperature during the surgical procedure. The duration of the surgical procedure per animals was kept below 15 minutes. A silicon rubber-coated 6.0 nylon monofilament (6021PK10, Doccol, Redlands, Calif., USA) was advanced through the carotid artery up to the origin of the middle cerebral artery (MCA) causing an MCA infarction. After an occlusion time of 60 min, the filament was removed allowing reperfusion. Animals were sacrificed 24 h after reperfusion and brains were checked for intracerebral hemorrhages. The extent of infarction was quantitatively assessed 24 hours after reperfusion on 2,3,5-triphenyltetrazolium chloride (TTC, Sigma-Aldrich) (2% (w/v) solution) stained brain sections. Planimetric measurements of infarcted areas (ImageJ software, NIH, Bethesda, Md., USA) corrected for brain edema were performed in a blinded fashion.

Bleeding Time Assay

Mice were anesthetized by intraperitoneal injection of triple anesthesia and a 2-mm segment of the tail tip was removed with a scalpel. Tail bleeding was monitored by gently absorbing blood with filter paper at 20 s intervals without directly contacting the wound site. When no blood was observed on the paper, bleeding was determined to have ceased. The experiment was manually stopped after 20 min by cauterization.

Thrombus Formation on Collagen Under Flow In Vitro

For adhesion to collagen, coverslips were coated with 200 μg mL⁻¹ collagen I at 37° C. o/n and blocked for 1 h with 1% BSA in PBS. Whole blood (700 μl+300 μl heparin (20 U/ml in TBS, pH7.3)) was diluted 2:1 in Tyrode's buffer containing Ca²⁺ and filled into a 1 ml syringe. Before perfusion, anticoagulated blood was incubated with Dylight-488-conjugated anti-GPIX derivative (0.2 μg/mL) at 37° C. for 5 minutes. Transparent flow chambers with a slit depth of 50 μm, equipped with the coated coverslips, were connected to a syringe that was filled with diluted whole blood. Perfusion was performed using a pulse-free pump under high shear stress equivalent to a wall shear rate of 1000 s⁻¹ or 1,700 s⁻¹. Aggregate formation was visualized with a Zeiss Axiovert 200 inverted microscope (40 x/0.60 objective). Phase-contrast and fluorescence pictures were recorded with a CoolSNAP-EZ camera, and analyzed off-line using MetaVue software.

Statistical Analysis

Results are shown as mean±SD from at least three individual experiments per group. When applicable Fisher's exact test was used for statistical analysis. Otherwise, the Welch's t test was performed for statistical analysis. P-values <0.05 were considered statistically significant. 

1. A method for the treatment and/or prevention of a thrombotic disease in a subject, comprising administering to the subject an effective amount of a soluble polypeptide comprising a modified glycoprotein V (GPV) lacking a functional transmembrane domain.
 2. The method according to claim 1, wherein the thrombotic disease is selected from the group consisting of thrombo-inflammatory conditions, venous thrombosis, arterial thrombosis, capillary thrombosis, portal vein thrombosis, renal vein thrombosis, jugular vein thrombosis, cerebral venous sinus thrombosis, thrombus formation during or after contacting blood with an artificial surface, atherosclerosis, arthritis, coagulopathy, deep venous thrombosis (DVT), disseminated intravascular coagulopathy (DIC), a chronic or acute thromboembolism, pulmonary thromboembolism, Budd-Chiari syndrome, Paget-Schroetter diseases, stroke, and myocardial infraction.
 3. The method according to claim 1, wherein the modified GPV is a truncated GPV.
 4. The method according to claim 1, wherein the modified GPV consists of a fragment of the extracellular domain of a native GPV, wherein the fragment lacks the transmembrane domain of the native GPV.
 5. The method according to claim 4, wherein the native GPV consists of the amino acid sequence of SEQ ID NO:3.
 6. The method according to claim 1, wherein the soluble polypeptide is a non-naturally occurring polypeptide.
 7. The method according to claim 6, wherein the soluble peptide further comprises a half-life-extending moiety.
 8. The method according to claim 7, wherein the half-life-extending moiety is conjugated to the modified GPV.
 9. The method according to claim 8, wherein the half-life-extending moiety is selected from the group consisting of hydroxyethyl starch (HES), polyethylene glycol (PEG), polysialic acids (PSAs), and albumin binding ligands.
 10. The method according to claim 7, wherein the half-life-extending moiety is a heterologous amino acid sequence fused to the modified GPV, either directly or via a linker.
 11. The method according to claim 10, wherein the heterologous amino acid sequence comprises or consists of a polypeptide selected from the group consisting of albumin and a fragment thereof having a length of at least 100 amino acids, immunoglobulin constant regions and fragments thereof, transferrin and fragments thereof, the C-terminal peptide of human chorionic gonadotropin, solvated random chains with large hydrodynamic volume (XTEN), homo-amino acid repeats (HAP), proline-alanine-serine repeats (PAS), afamin, alpha-fetoprotein, Vitamin D binding protein, polypeptides capable of binding under physiological conditions to albumin or immunoglobulin constant regions, and combinations thereof.
 12. The method according to claim 1, wherein the soluble polypeptide is obtained by recombinant expression in mammalian cells.
 13. The method according to claim 1, further comprising administering to the subject an anti-platelet or an anti-coagulant drug.
 14. A pharmaceutical composition comprising a soluble polypeptide comprising a modified GPV lacking a functional transmembrane domain, and a pharmaceutically acceptable excipient.
 15. The pharmaceutical composition of claim 14, wherein the soluble polypeptide does not consist of the amino acid sequence of SEQ ID NO:10.
 16. A method of treating a thrombotic disease in a subject, comprising administering to the subject an effective amount of the pharmaceutical composition of claim
 14. 17. A method of preparing a soluble polypeptide, comprising expressing a nucleic acid encoding the soluble polypeptide in a mammalian cell, culturing the mammalian cell in a culture medium, and recovering the soluble polypeptide from the culture medium, wherein the soluble polypeptide comprises a modified GPV lacking a functional transmembrane domain.
 18. A non-naturally occurring soluble GPV lacking a functional transmembrane domain.
 19. A soluble GPV lacking a functional transmembrane domain, wherein the soluble GPV does not consist of the amino acid sequence of SEQ ID NO:10.
 20. A pharmaceutical kit comprising (i) a soluble polypeptide comprising a modified GPV lacking a functional transmembrane domain, and (ii) an anti-platelet or an anti-coagulant drug other than the soluble polypeptide.
 21. The method of claim 1, wherein the thrombotic disease is thrombus formation during or after extracorporeal membrane oxygenation (ECMO).
 22. The method of claim 8, wherein the half-life-extending moiety is a fatty acid chain.
 23. The method of claim 10, wherein the heterologous amino acid sequence comprises an Fc fragment. 